US5273651A - Disc filter - Google Patents

Disc filter Download PDF

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Publication number
US5273651A
US5273651A US07/923,918 US92391892A US5273651A US 5273651 A US5273651 A US 5273651A US 92391892 A US92391892 A US 92391892A US 5273651 A US5273651 A US 5273651A
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United States
Prior art keywords
filter
sector
disc
axial
outlet
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Expired - Fee Related
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US07/923,918
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English (en)
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Harry Nilsson
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Individual
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Individual
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/15—Filters with filtering elements which move during the filtering operation with rotary plane filtering surfaces
    • B01D33/21—Filters with filtering elements which move during the filtering operation with rotary plane filtering surfaces with hollow filtering discs transversely mounted on a hollow rotary shaft
    • B01D33/215—Filters with filtering elements which move during the filtering operation with rotary plane filtering surfaces with hollow filtering discs transversely mounted on a hollow rotary shaft the filtering discs being fixed inwardly on a rotating construction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/70—Filters with filtering elements which move during the filtering operation having feed or discharge devices
    • B01D33/74—Filters with filtering elements which move during the filtering operation having feed or discharge devices for discharging filtrate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2201/00—Details relating to filtering apparatus
    • B01D2201/28—Position of the filtering element
    • B01D2201/282—Filtering elements with a horizontal rotation or symmetry axis

Definitions

  • the present invention concerns an arrangement in a disc filter including at least one filter disc partly submerged in a vessel for liquid or suspension to be filtered, said filter disc including a plurality of substantially annularly disposed filter sectors and being rotatable about a collecting trough for solid substance deposited on the outside of the filter sectors and falling down therefrom, each filter sector having a filtrate outlet by means of which the interior of the filter sector communicates with an axial channel for discharge of filtrate, and said filtrate outlet being arranged at the edge of the filter sector trailing upon rotation of filter disc and being connected to the side of the axial channel leading in the direction of rotation.
  • Filters of this kind are mainly used in cellulose and pulp industry for thickening fiber suspensions and for cleaning process water, so called fiber recovery.
  • the axial channels are centrally arranged and form, together with cross-channels extending between the axial channels, part of the annular rotor surrounding the collecting trough.
  • the filter sectors being carried by and communicating with each one cross channel in turn communicating with an axial channel, extend substantially radially and approximately fan-like outwards from the rotor.
  • the rotor must have a certain minimum diameter to accommodate an appropriate collecting trough, while on the other hand as small a rotor diameter (i.e., the inner diameter of the filter disc) as possible is desirable to obtain the largest possible filter area without the outer diameter of the filter disc becoming much too large.
  • the axial channels are arranged at the outer circumference of each filter disc.
  • the central opening of the filter is entirely free from every obstacle for solid substance falling from the filter sectors.
  • such a filter is also made with cross-channels comprising sections of an annular channel arranged at the outer periphery of a filter disc, each such section communicating with an axial channel.
  • a combination of the two filter types mentioned, i.e, provision of a filter having filter sectors extending radially outward of as well as radially inward of the axial channels hitherto has not been possible eliminating the respective drawbacks.
  • This relates to removal of the filter cake deposited on a filter sector. Such removal is initiated at the outer periphery of a filter disc in that a water jet is directed obliquely against the filter sectors in a certain position of rotation of the filter disc. The water jet loosens a portion of the filter cake from a filter sector, whereafter the filter cake continuously "rolls" off the filter sector in one integral piece.
  • the object of the present invention is to set aside the problems of the known filters by creating a filter without cross-channels still having optimum filtering capacity, i.e., largest possible filter area having smallest possible outer diameter without the opening diameter of a filter disc for that reason being too small.
  • the filtrate outlet in manner known per se through SE-B-447 208, is arranged at the edge of the filter sector trailing on rotation of the filter disc and connected to the side of the axial channel leading in the direction of rotation, cross-channels are avoided, whereby is obtained an integral filter cake which may be removed in one piece without problem even when a filter sector according to claim 1 extends radially outward of as well as radially inward of an axial channel.
  • the diameter of the filter disc can be made smaller for given filter area due to the fact that also the space inwardly of the axial channels can be utilized.
  • the filter cake will not be hanging on a trailing axial channel because the radial extension of the sector outside the sector is less than if the sector would extend only radially outwards from an axial channel. Therefore, the falling distance of a fiber cake radially inwards towards the path of moment of the axial channels becomes so short that the trailing axial channel being advanced towards the falling path of the fiber cake due to the rotation will not be advanced so far that it risks to be hit by the falling fiber cake.
  • FIG. 1 is a cross-section along line I--I of FIG. 4 through a filter arranged according to a preferred embodiment of the invention
  • FIG. 2 shows a portion of a filter disc having another arrangement of the filter sectors
  • FIG. 3 shows a portion of a filter sector having still another arrangement of the filter sectors
  • FIG. 4 is a section along line IV--IV of FIG. 5 through a filter according to FIG. 1 but without filter sectors,
  • FIG. 5 shows a view of the filter according to FIGS. 1 and 4 seen from the left of FIG. 4, likewise without filter sectors,
  • FIG. 6 is a section at a larger scale through an axial filtrate conduit along line VI--VI of FIG. 4,
  • FIG. 7 shows a view of a portion of an axial filtrate conduit seen along line VII-VII of FIG. 6, and
  • FIG. 8 shows a detail at an enlarged scale of a filter sector and a corresponding axial filtrate conduit.
  • a filter rotate 2 is partly submerged under the liquid level L, and rotate including a plurality of filter discs 3.
  • Each filter disc 3 in turn includes a plurality of filter sectors 4 annularly disposed such that an opening 5 is formed in the center thereof.
  • a collecting trough 6 intended to catch solid substance falling down from the filter sectors.
  • a discharge screw 7 for removal of solid substance collected in the through.
  • each filter sector 4 has two spaced layers of filter cloth 4' and corresponding filtering means through which the liquid contained in vessel 1 is filtered.
  • solid substance is deposited on the outside of the filtering means while filtrate flows therethrough to the interior of the filter sector.
  • axial filtrate conduits 8 which, through substantially radial filtrate conduits 9, lead to a central outlet 10 at one end of the filter.
  • the axial filtrate conduits 8 as well as the substantially radial filtrate conduits 9 form parts of the filter rotor 2 and make up its structural body carrying the filter sectors 4.
  • the number of axial filtrate conduits 8 corresponds to the number of filter sectors 4 of each filter disc 3, to each axial filtrate conduit being after each other connected one filter sector of each filter disc.
  • the outlet 10 is of the common rotating kind and is adapted to successively put the radial filtrate conduit 9 and thereby the axial filtrate conduits 8 in connection with a non-shown source of under-pressure.
  • the axial filtrate conduits are connected to a circular support ring 11 against the inside of which run non-shown support means for the filter rotor.
  • each filter sector is connected to an axial filtrate conduit through a circumferentially directed cross-channel.
  • each filter sector 4 is connected with its edge trailing in the direction of rotation to an axial filtrate conduit 8.
  • This connection is arranged on a portion of the axial filtrate conduit turned substantially upwards at rotation of the filter rotor when the axial filtrate conduit raises above the liquid surface L.
  • This arrangement has enabled mounting of filter sectors such that they extend radially inwards (FIG. 2), radially outwards (FIG. 3) or at the same time radially inwards and outwards (FIG. 1) from the axial filtrate conduit 8.
  • the axial filtrate conduits 8 have the cross-sectional shape best appearing from FIGS. 6 and 8, i.e., substantially triangular having a longer side 12 and two shorter sides 13 and 14.
  • the longer side 12 which is turned upwards when the axial filtrate conduit raises above the liquid level L, is arranged a number of openings 15 corresponding to the number of filter discs.
  • a filter sector 4 is mounted against each such opening 15 such that its interior communicates with the interior of the axial filtrate conduit 8 in question through a corresponding opening 16 (FIG. 8) in a trailing edge of the filter sector.
  • the longer side 12 provides a relatively long distance of connection for a filter sector and thereby a large area of opening 15 as well as a stable attachment of the filter sector.
  • the longer side 12 merges into the shorter sides 13 and 14 through curved surfaces 17 and 18, such that a large interior cross-section is created.
  • the shorter sides 13 and 14 are interconnected by a tip 19 which is turned substantially downwards when the axial filtrate conduit raises above the liquid level L.
  • a tip 19 having two sides 13 and 14 inclining towards the tip 19.
  • the filter sector may be mounted such that it extends either radially inwards or radially outwards from the axial filtrate conduit.
  • filter sectors can be used which according to FIG. 1 extend radially inwards as well as radially outwards from the axial filtrate conduits.
  • Such a filter sector is shown separately in FIG. 8 together with a corresponding axial filtrate conduit 8.
  • this filter sector 4 has an outer arcuate edge 20 from which an edge 21 foremost in the rotational direction and an edge 22 aftmost or trailing in the direction of rotation extend towards the center.
  • the trailing edge 22 is divided in a radially outer straight edge portion 22a and a radially inner likewise straight edge portion 22b.
  • the edge portions 22a and 22b form such an angle that these edge portions incline downwards towards the axial filtrate conduit 8 to which the filter sector in question is connected when this filter sector and its corresponding axial filtrate conduit raise above the liquid level L. This appears clearly from FIG.
  • edges 21 of the filter sectors 4 leading in the rotational direction comprise two mutually angled portions 21a and 21b (FIG. 8).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtration Of Liquid (AREA)
  • Centrifugal Separators (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Surgical Instruments (AREA)
US07/923,918 1990-02-26 1991-02-26 Disc filter Expired - Fee Related US5273651A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9000685-9 1990-02-26
SE9000685A SE465605B (sv) 1990-02-26 1990-02-26 Skivfilter

Publications (1)

Publication Number Publication Date
US5273651A true US5273651A (en) 1993-12-28

Family

ID=20378687

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/923,918 Expired - Fee Related US5273651A (en) 1990-02-26 1991-02-26 Disc filter

Country Status (10)

Country Link
US (1) US5273651A (sv)
EP (1) EP0516731B1 (sv)
JP (1) JP3086251B2 (sv)
AT (1) ATE122252T1 (sv)
BR (1) BR9106086A (sv)
CA (1) CA2076852C (sv)
DE (1) DE69109669T2 (sv)
FI (1) FI93429C (sv)
SE (1) SE465605B (sv)
WO (1) WO1991012872A1 (sv)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11000791B2 (en) * 2019-03-06 2021-05-11 Veolia Water Solutions & Technologies Support Rotary disc filter having backwash guides

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0229804D0 (en) * 2002-12-20 2003-01-29 Syngenta Participations Ag Avermection b1 and avermectin b1 monosaccharide derivatives having an alkoxymethyl substituent in the 4"- or 4'-position
FI129909B (sv) * 2021-10-12 2022-10-31 Valmet Technologies Oy Kontinuerlig skivfilteranordning

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4056473A (en) * 1976-05-25 1977-11-01 Bjarne Ivar Nilsson Rotary filter for concentrating fiber suspensions
SE447208B (sv) * 1982-12-22 1986-11-03 Celleco Ab Roterbart filter
US4634529A (en) * 1983-10-21 1987-01-06 Bjarne Nilsson Rotatable disc filter
US4678575A (en) * 1982-08-20 1987-07-07 Ab Celleco Rotatable filter disc assembly
EP0297074A1 (en) * 1987-06-24 1988-12-28 Bjarne Nilsson Disc sector for rotary disc filter
WO1988010144A1 (en) * 1987-06-24 1988-12-29 Bjarne Nilsson Rotating filter with outer filtrate conduits

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4056473A (en) * 1976-05-25 1977-11-01 Bjarne Ivar Nilsson Rotary filter for concentrating fiber suspensions
US4678575A (en) * 1982-08-20 1987-07-07 Ab Celleco Rotatable filter disc assembly
SE447208B (sv) * 1982-12-22 1986-11-03 Celleco Ab Roterbart filter
US4634529A (en) * 1983-10-21 1987-01-06 Bjarne Nilsson Rotatable disc filter
EP0297074A1 (en) * 1987-06-24 1988-12-28 Bjarne Nilsson Disc sector for rotary disc filter
WO1988010144A1 (en) * 1987-06-24 1988-12-29 Bjarne Nilsson Rotating filter with outer filtrate conduits
US4931179A (en) * 1987-06-24 1990-06-05 Bjarne Nilsson Filter section for a rotatable filter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11000791B2 (en) * 2019-03-06 2021-05-11 Veolia Water Solutions & Technologies Support Rotary disc filter having backwash guides

Also Published As

Publication number Publication date
JP3086251B2 (ja) 2000-09-11
EP0516731A1 (en) 1992-12-09
FI923745A0 (sv) 1992-08-20
JPH05508340A (ja) 1993-11-25
SE9000685D0 (sv) 1990-02-26
WO1991012872A1 (en) 1991-09-05
SE9000685L (sv) 1991-08-27
FI93429B (sv) 1994-12-30
FI93429C (sv) 1995-04-10
DE69109669T2 (de) 1995-09-14
ATE122252T1 (de) 1995-05-15
BR9106086A (pt) 1993-03-09
DE69109669D1 (de) 1995-06-14
EP0516731B1 (en) 1995-05-10
CA2076852A1 (en) 1991-08-27
CA2076852C (en) 2001-12-11
SE465605B (sv) 1991-10-07
FI923745A (sv) 1992-08-20

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